Liquid degasifying system



Jan. 13, 1970 A. GIARBG-Asr A LIQUID DE'GASIFYING SYSTEM Filed Dec. 11,19e? k R A. o -LEI MT IsmtkQhhal NQ mmmrg-h .H M m .Nw e d Kwltwkb m mTm .M R A pvf 6 M I1 A .171. V I! L Q n A n1 wm xlw m A, Q M .lr/ MII.wkwk \\\\\\\N\\\\\\\\\.\\\\\`\\ Y Wm ONM? w\ QWwbQWWQ NN WQ@ mm. w l\Lw: Sn \\\.\\\\\\-\\\\\\\\\\\u d 1J ATTORNEY United States Patent O3,488,925 LIQUID DEGASIFYING SYSTEM Alva G. Arbogast, Box 1139,Charleston, W. Va. 25324 Filed Dec. 11, 1967, Ser. No. 689,431 Int. Cl.B01d 19/00 U.S. Cl. 55-192 1 Claim ABSTRACT OF THE DISCLOSURE Adegasifying system for use in the treatment of liquid to -be used inindustrial process work. The system includes a liash chamber atatmospheric pressure containing condenser coils. The liquid is initiallyfed through these condenser coils, which are maintained at a relativelylow temperature by the incoming liquid. From the condenser coils theliquid goes through a heat exchanger, heated by steam at about 250 F.The hot liquid is released into the ash chamber through a back pressurerelief valve. The ashing hot liquid vaporizes and contacts the condensercoils, recondensing and flowing to a storage receptacle. In flashing,the the liquid gives up oxygen, air, or other gases previously containedtherein.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to systems for degasifying liquids, and more particularly to asystem for the degassing treatment of water to be subsequently employedin industrial processes.

Description of the prior art Fluid handling systems have heretoforeproposed the expulsion of super-heated fluids into expansion chambersfor various purposes.

SUMMARY OF THE INVENTION A main object of the invention is to provide anovel and improved liquid degasifying system which involves relativelysimple apparatus, which is reliable in operation, and which eliicientlyremoves air, dissolved oxygen, aromatic gases, or other foreignmaterials from liquid intended to be subsequently employed in industrialprocesses.

A further object of the invention is to provide an improvedwater-degasifying system which can be installed in a relatively smallspace, which is economical to operate, and which employs relativelyinexpensive components.

A still further object of the invention is to provide an improvedwater-degasifying system for use in treating water from boilers, or fromany other source, to remove undesired gases or other foreign substancestherefrom, the system employing a liquidpashing technique which ishighly eiective in separating the undesired gases or other materialsfrom the water, the system employing components which are easy tooperate and to maintain in proper working order, the system having arelatively high ilow capacity, and the system being particularlyrsuitable for continuous or long-term uninterrupted operation withoutrequiring any substantial amount of human supervision.

A still further object of the invention is to provide an improved 'Waterdegasication system which is easy to install, which is safe to operate,and which provides a dependable continuous supply of purified degassedwater for use in industrial processes requiring same.

Further objects and advantages of the invention will 3,488,925 PatentedJan. 13, 1970 ICC become apparent from the following description andclaims, and from the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single iigure of the drawingdiagrammatically and schematically illustrates a typical waterdegasifying system constructed n accordance with the present invention,with certain parts thereof being shown in longitudinal and verticalcrosssection.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, 11designates a flash chamber having the generally cylindrical longitudinalwall 12 and the respective front and rear end walls 13 and 14. Au inletconduit 15, for water to be degassed, extends sealingly through frontend wall 13 to the rear end of a longitudinally extending condenser coil16- mounted substantially axially in the fonward end portion of chamber11. The condenser coil has the outlet conduit 17 extending sealinglythrough the lower portion of wall 13, as shown.

Substantially centrally mounted in front end wall 13 is a relativelysmall-diameter gas release conduit litting 18 connected to a downwardypitched conduit 19 leading to a waste conduit 20 under atmosphericpressure. Conduit 19 is downwardly pitched from gas release fitting 1Sto minimize the return of sour gas back into the liash chamber 12 and tothereby minimize recontamination of the degassed liquid obtained by thesystem.

Chamber 11 is provided with a bottom discharge conduit 21 in Wall 12adjacent end wall 13. Conduit 21 is connected through a water seal unit22 and a conduit 23 to a storage tank 24 for degassed water to beeventually used in an industrial process.

Water seal unit 22 is protected against siphoning by the provision of ananti-Siphon vent conduit 25 connecting theY top of the inverted -waterseal U-bend 26 to the vapor space 27 in the upper portion of tank 24.

Designated at 27 is a conventional heat exchanger comprising anelongated chamber 28 having the opposite outwardly convex end walls 29Eand 30, with a vertical partition plate 31 mounted therein adjacent endwall 30. A transverse horizontal partition plate 32 is centrally securedbetween plate 31 and end wall 30, defining upper and lower compartments33 and 34. A plurality of U- shaped horizontally extending heatexchanger tubes 35 are provided in chamber 28, with their inlet endssecured in the lower portion of plate 31, in communication withcompartment 34, and their outlet ends secured in the upper portion ofplate 31, in communication with compartment 33. Chamber 28 is providedin its top wall adjacent plate 31 with a steam inlet conduit 36 and inits bottom wall adjacent end wall 29 with an outlet conduit 37.

Conduit 37 is connected through a conventional steam trap 38 and a checkvalve 39 to the lower region of storage tank 24.

A source of steam is connected by a conduit 40 through a conventionalpressure-regulating valve 41 to inlet conduit 36. The steam suppliedthrough conduit 40 may be under any pressure suthcient to provide steamat the required pressure to line 3'6. The pressure-regulating valve 41is set to provide an outlet pressure of 15 pounds per square inch gauge,which is therefore at a temperature of about 250 F. The input steampressure in supply line 40 may be, for example, between 50 and 150pounds per square inch gauge.

A conventional pressure gauge 43 may be provided, connected to line 36.

The outlet conduit 17 of condensing coil 16 is connected to an inletconduit 44 in the lower p-ortion of end wall 30 communicating withcompartment 34, and thus with the inlet ends of tubes 35. An outletconduit 45 is provided in the upper portion of Wall 30, communicatingwith compartment 33, and thus with the outlet ends of tubes 35. Conduit45 is connected to the rear end of Hash chamber 11 through aspring-loaded back pressure relief valve 46. The spring 47 of reliefvalve 46 is designed to maintain a back pressure in conduit 45 ofapproximately 15 pounds per square inch gauge and to allow the valvedisc element 48 thereof to unseat when this designated pressure isreached or exceeded. This valve action permits the water in tubes 35 tobe heated to a temperature much higher than 212 F., thus providing theheat necessary to :ause ashing of the gas-bearing water as it entersHash chamber 11, as will be presently described.

Valve 46 is connected to the Hash chamber 11 through a relatively shortinlet conduit 49 centrally mounted in rear Wall 14. A baHie plate 50 ismounted on the rear and of condensing coil 16, facing inlet conduit 49,but spaced therefrom by the Hash space 51.

In operation, water containing dissolved oxygen and/ or othernon-condensable gases enters the degasifying system through conduit 15and passes through the condensing coil 16. The temperature of theincoming water .is Jelow 100 F. This relatively low temperature keepsthe surface temperature of the coil 16 cool enough to con- :lense anysteam coming into contact with its surface.

The non-condensable gas released within the Hash :hamber 11 is ventedout of the system through the gas release fitting 18 and conduit 19 tothe waste conduit 20 Jnder atmospheric pressure. As above mentioned,conduit 19 is pitched downwardly from gas release titting 18 to ninimizethe possibility of sour gas flowing back into chamber 11. This avoidsrecontamination of the degassed liquid in the system.

Gas-bearing water Hows from coil 16 through conduit l7 into compartment34 and thence through the steamheated tubes 35 of heat exchanger 27. Thesteam inside the chamber 28 surrounding the tubes 35 is maintained at 15pounds per square inch gauge, with a correspondlng saturated temperatureof 250 F.

The condensate in the heat exchanger chamber 28, resulting from contactof the steam with the tubes 35, :irains off through conduit 37, sterntrap 38 and check valve 39 into the storage tank 24.

Gas-bearing water at 250 F. leaves tubes 35 through :ompartment 33 andconduit 45'and enters the back Jressure relief valve 46 at 250 F.

The pressure of the gas-bearing Water Howing into the Jalve 46 ismaintained close to 15 pounds per square inch gauge by the biasingaction of the spring 47 on the valve.

iisc element 48. This valve action permits heating the Yvater to atemperature much higher than 212 F., thus nroviding the heat necessaryto cause Hashing of the gas- Jearing water responsive to the unseatingof valve disc :lement 48, which occurs as a result of the pressurebuildip beneath the disc element. The water Hashes into steam 1s itenters the Hash chamber 11 through the short coniuit 49, the chamber 11being at a pressure only slightly nore than atmospheric, wherein thecorresponding water )oiling point is only slightly higher than 212 F.

Chamber 11 operates at a pressure slightly higher than xtmosphericbecause of the water seal 22 and the restric- .ion caused by therelatively small-diameter outlet coniuit 18. This pressure is of theorder of 2 to 3 inches )f water above atmospheric pressure. As abovemenioned, the water seal 22 cannot siphon because it is proected fromsiphoning by conduit 25 which is connected o the vapor space of thestorage tank 24.

When Hashing occurs in space 51, the undesired oxygen water, separateout, the separation action being aided by the impact of the Hashedliquid against the baie plate 50, although it is mainly caused by thesudden expansion which occurs when the superheated liquid Hashes intosteam.

As the Hashing water enters the chamber 11, heavy liquid particles fallto the bottom of the chamber and the Hash steam and liberated gasesbreak free in the space 51 inside the chamber. This steam and gasmixture strikes the baHie plate 50, which forces it to flow into thespace surrounding coil 16.

The degasied water vapor condenses as a result of contact with thecondensing coil 16, and all the resultant degasiiied water dischargesthrough conduit 21 and water seal 22 to the conduit 23 and thence to thestorage tank 24, completing the cycle.v

While a specific embodiment of an improved water degasifying system hasbeen disclosed in the foregoing description, it will be understood thatvarious modilications within the spirit of the invention may occur tothose skilled in the art. Therefore it is intended that no limitationsbe placed on the invention except as defined by the scope of theappended claims.

I claim:

1. In a liquid degassing system: a Hash chamber having a forward endwall and a rear end wall and a horizontal axis; means substantiallyventing said Hash chamber to atmosphere comprising a relatively smalldiameter gas vent conduit mounted in the forward end wall of the flashchamber, said gas vent conduit being downwardly pitched from itsconnection with said forward end wall to minimize the return of gas backinto the Hash chamber; a longitudinally extending condenser coil mountedsubstantially axially in the forward end portion of the chamber; abaffle plate transversely mounted on the rear end of said condensercoil; a source of water to be degassed; conduit means connecting saidsource to one end of the condenser coil; a heat exchanger having heatexchanger tubes, a heating space surrounding said tubes, and respectiveinlet and outlet spaces in communication with the ends of the tubes;conduit means connecting the outer end of the condenser coil to saidinlet space; a source of superheated steam at a temperature of the orderof 250 F.; conduit means connecting said last-named source to saidheating space; said Hash chamber rear wall being provided with asubstantially centrally-located, relatively short inlet conduit; conduitmeans connecting the outlet space of the heat exchanger to said shortinlet conduit; a spring-loaded back pressure relief valve in saidlastnamed conduit means located adjacent said inlet conduit and having aloading spring designed to maintain a back pressure in said last-namedconduit means corresponding to a water temperature substantially higherthan 212 F., whereby to provide the heat necessary to cause flashing ofgas-bearing water as it enters the Hash chamber, storage means fordegassed water; and conduit means located to the forward wall connectingthe bottom of the Hash charnber to said storage means.

References Cited UNITED STATES PATENTS 2,515,648 7/1950 Hunt et al.55-166 X 2,556,107 6/1951 Roswell 165-40 2,908,618 10/1959 Bethon202-180 X REUBEN FRIEDMAN, Primary Examiner R. W. BURKS, AssistantExaminer

